Nine out of 10 students from middle and upper-class New Hampshire families graduate from high school, while only 73 percent of low-income students earn a diploma, according to a report on national high school graduation rates.

Building a GradNation was released Monday by a consortium that included America's Promise Alliance, which was founded by former Secretary of State Colin Powell to focus attention on children and teens.

Overall, the report found the 2012 graduation rate for the nation topped 80 percent, the first time ever. New Hampshire had a graduation rate of 86 percent; only seven other states topped the Granite State.

But New Hampshire had an 18-percent "opportunity gap" between affluent/middle class graduates and those from low-income households.

"Certainly, we continue to have work to do with certain populations in certain communities in the state," said Paul Leather, deputy New Hampshire commissioner of education. Those communities include Manchester and Rochester, which have large populations of low-income Hispanic and African-Americans and other economically disadvantaged students, he said.

GradNation focuses on the gap. It noted that in southern and Midwestern states, graduation rates for black males are in the upper 50 and low 60s.

"Our nation cannot prosper nor retain true to its ideals when far too many young men of color are still not receiving the supports and opportunities needed to obtain a high school diploma," the report reads.

Data in the report show a consistent improvement in New Hampshire graduation rates over the past 10 years.New Hampshire graduated 91 percent of middle class/affluent students in 2012, compared to 73 percent of students on free or reduced school lunch. Nationally, the graduation rates are not as high, but the gap is slightly narrower — 87 percent to 72 percent.

The report said that both Hispanics and blacks saw significant increases in graduation rates in the past six years. In part, it attributed the changes to a reduction in "dropout factories," which it describes as large urban schools with high concentrations of low-income students and high dropout rates.

New Hampshire had only one dropout factory in 2012, according to report data. The report does not name the school, but Leather said he presumes it is Manchester High School West. The school has a new principal, and graduation rates should start improving in the 2014 year, he said.

He also said the expansion of the Manchester School of Technology and the STEAM Ahead program at West should help improve the city's graduation rate.

The report calls for several national strategies to reach the goal of 90 percent graduation rate by 2020:

• Improve the graduation rate of students with disabilities, who have significantly lower graduation rates.

• Concentrate on California, and make it a focus of national attention. California has the highest poverty rate, a high rate of household income and a population that is 61 percent non-Anglo, yet it remains a laboratory of innovation in education reform.

• Concentrate on young men of color, who show improvement but lag behind other subgroups.